Patent GB-738609-A (GB)
Title: Improvements in or relating to anti-set-off spraying apparatus for use with printing machinery, also applicable to other apparatus
IPC: B41F23/06
Filed: 1953-03-12
Abstract: 738,609. Spray-producers. WALLER, J. R. March 26, 1954 [March 12, 1953], No. 6808/53. Class 69 (3). [Also in Group XVI] A powder or liquid spray apparatus, e.g. for use with printing-machines to prevent set-off from newly-printed sheets or webs comprises a pipe system through which a stream of air is circulated by a pump in a closed circuit, a spray of liquid or powder being injected into the stream of air, the air current leaving the pipe system at one point, impinging on a printed sheet travelling past the apparatus and returning to the pipe system again. The air stream passes under pressure from pump 7 through pipe 4 to a spray tube 9, Figs. 2, 4, formed with a series of longitudinal slots 9a, Fig. 4, directed downwardly towards an adjustably-mounted reflector plate 12,. over which the newly-printed sheets are passed for stacking. In the absence of a sheet the plate 12 reflects the stream so that the powder or liquid therein is not lost into the atmosphere. Parallel to tube 9 is a return tube 10 similarly formed with slots and connected to the suction side of the pump. The air stream after impinging on the sheet or plate 12 is drawn into the system again through the slots 10a. Baffle-plates 11 attached to the outer sides of the tubes 9, 10 serve to confine the powder or liquidladen air stream so as to prevent loss as far as ,possible. The end of tube 9 is closed by a cap which, it is stated, causes an increase in pressure in the central portion of the tube 9. For this reason the discharge slots are made narrower near the central portion of tube 9 to produce a uniform discharge of spray. The ends of the tubes 9 and 10 may alternatively be connected back to their supply pipes 4, 5. The spray distribution may further be regulated by spring clips having tongues of varying lengths to fit into the slots 9a and cause deflection of the air-stream out through the corresponding slots. The powder or liquid is introduced into the return pipe 24 of the pump 7 by a device shown in Fig. 3. A container 1 for the powder or liquid has a conical liner 45 into which fits a bored conical member 17 having a threaded shank forming a nozzle 16 screwing into a sleeve member 18. At the lower end the sleeve 18 is attached by screws or rivets to the pipe 24 and carries a spigot closed at the end but formed with a through bore 49. Passage of air past the spigot causes a low pressure to be formed in the bore 49 which is transmitted through the passage 28 in' sleeve 18 to the nozzle 16. A rod 20 fitting with a small clearance in the bore in member 17 and nozzle 16, is connected at its upper end to an arm 21. The arm forms part of an electrical vibrator 22 and staggered vanes or arms 23 arranged in helical formation are provided on the rod 20 so that the powder or liquid in the container is kept in a constant state of agitation. The space 43 below the nozzle 16 may be connected to atmosphere by a cock-tap 27 admitting an adjustable flow of air. The flow of powder (or liquid) and air may be con. trolled by a throat bored transversely through a screwed member 2, itself positioned in a bore transverse of passage 28. The throat member 2 may be exchanged to change the size of the regulating throat.